xref: /openbmc/linux/drivers/platform/x86/hdaps.c (revision 1eb4c977)
1 /*
2  * hdaps.c - driver for IBM's Hard Drive Active Protection System
3  *
4  * Copyright (C) 2005 Robert Love <rml@novell.com>
5  * Copyright (C) 2005 Jesper Juhl <jesper.juhl@gmail.com>
6  *
7  * The HardDisk Active Protection System (hdaps) is present in IBM ThinkPads
8  * starting with the R40, T41, and X40.  It provides a basic two-axis
9  * accelerometer and other data, such as the device's temperature.
10  *
11  * This driver is based on the document by Mark A. Smith available at
12  * http://www.almaden.ibm.com/cs/people/marksmith/tpaps.html and a lot of trial
13  * and error.
14  *
15  * This program is free software; you can redistribute it and/or modify it
16  * under the terms of the GNU General Public License v2 as published by the
17  * Free Software Foundation.
18  *
19  * This program is distributed in the hope that it will be useful, but WITHOUT
20  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
21  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
22  * more details.
23  *
24  * You should have received a copy of the GNU General Public License along with
25  * this program; if not, write to the Free Software Foundation, Inc.,
26  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
27  */
28 
29 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
30 
31 #include <linux/delay.h>
32 #include <linux/platform_device.h>
33 #include <linux/input-polldev.h>
34 #include <linux/kernel.h>
35 #include <linux/mutex.h>
36 #include <linux/module.h>
37 #include <linux/timer.h>
38 #include <linux/dmi.h>
39 #include <linux/jiffies.h>
40 #include <linux/io.h>
41 
42 #define HDAPS_LOW_PORT		0x1600	/* first port used by hdaps */
43 #define HDAPS_NR_PORTS		0x30	/* number of ports: 0x1600 - 0x162f */
44 
45 #define HDAPS_PORT_STATE	0x1611	/* device state */
46 #define HDAPS_PORT_YPOS		0x1612	/* y-axis position */
47 #define	HDAPS_PORT_XPOS		0x1614	/* x-axis position */
48 #define HDAPS_PORT_TEMP1	0x1616	/* device temperature, in Celsius */
49 #define HDAPS_PORT_YVAR		0x1617	/* y-axis variance (what is this?) */
50 #define HDAPS_PORT_XVAR		0x1619	/* x-axis variance (what is this?) */
51 #define HDAPS_PORT_TEMP2	0x161b	/* device temperature (again?) */
52 #define HDAPS_PORT_UNKNOWN	0x161c	/* what is this? */
53 #define HDAPS_PORT_KMACT	0x161d	/* keyboard or mouse activity */
54 
55 #define STATE_FRESH		0x50	/* accelerometer data is fresh */
56 
57 #define KEYBD_MASK		0x20	/* set if keyboard activity */
58 #define MOUSE_MASK		0x40	/* set if mouse activity */
59 #define KEYBD_ISSET(n)		(!! (n & KEYBD_MASK))	/* keyboard used? */
60 #define MOUSE_ISSET(n)		(!! (n & MOUSE_MASK))	/* mouse used? */
61 
62 #define INIT_TIMEOUT_MSECS	4000	/* wait up to 4s for device init ... */
63 #define INIT_WAIT_MSECS		200	/* ... in 200ms increments */
64 
65 #define HDAPS_POLL_INTERVAL	50	/* poll for input every 1/20s (50 ms)*/
66 #define HDAPS_INPUT_FUZZ	4	/* input event threshold */
67 #define HDAPS_INPUT_FLAT	4
68 
69 #define HDAPS_X_AXIS		(1 << 0)
70 #define HDAPS_Y_AXIS		(1 << 1)
71 #define HDAPS_BOTH_AXES		(HDAPS_X_AXIS | HDAPS_Y_AXIS)
72 
73 static struct platform_device *pdev;
74 static struct input_polled_dev *hdaps_idev;
75 static unsigned int hdaps_invert;
76 static u8 km_activity;
77 static int rest_x;
78 static int rest_y;
79 
80 static DEFINE_MUTEX(hdaps_mtx);
81 
82 /*
83  * __get_latch - Get the value from a given port.  Callers must hold hdaps_mtx.
84  */
85 static inline u8 __get_latch(u16 port)
86 {
87 	return inb(port) & 0xff;
88 }
89 
90 /*
91  * __check_latch - Check a port latch for a given value.  Returns zero if the
92  * port contains the given value.  Callers must hold hdaps_mtx.
93  */
94 static inline int __check_latch(u16 port, u8 val)
95 {
96 	if (__get_latch(port) == val)
97 		return 0;
98 	return -EINVAL;
99 }
100 
101 /*
102  * __wait_latch - Wait up to 100us for a port latch to get a certain value,
103  * returning zero if the value is obtained.  Callers must hold hdaps_mtx.
104  */
105 static int __wait_latch(u16 port, u8 val)
106 {
107 	unsigned int i;
108 
109 	for (i = 0; i < 20; i++) {
110 		if (!__check_latch(port, val))
111 			return 0;
112 		udelay(5);
113 	}
114 
115 	return -EIO;
116 }
117 
118 /*
119  * __device_refresh - request a refresh from the accelerometer.  Does not wait
120  * for refresh to complete.  Callers must hold hdaps_mtx.
121  */
122 static void __device_refresh(void)
123 {
124 	udelay(200);
125 	if (inb(0x1604) != STATE_FRESH) {
126 		outb(0x11, 0x1610);
127 		outb(0x01, 0x161f);
128 	}
129 }
130 
131 /*
132  * __device_refresh_sync - request a synchronous refresh from the
133  * accelerometer.  We wait for the refresh to complete.  Returns zero if
134  * successful and nonzero on error.  Callers must hold hdaps_mtx.
135  */
136 static int __device_refresh_sync(void)
137 {
138 	__device_refresh();
139 	return __wait_latch(0x1604, STATE_FRESH);
140 }
141 
142 /*
143  * __device_complete - indicate to the accelerometer that we are done reading
144  * data, and then initiate an async refresh.  Callers must hold hdaps_mtx.
145  */
146 static inline void __device_complete(void)
147 {
148 	inb(0x161f);
149 	inb(0x1604);
150 	__device_refresh();
151 }
152 
153 /*
154  * hdaps_readb_one - reads a byte from a single I/O port, placing the value in
155  * the given pointer.  Returns zero on success or a negative error on failure.
156  * Can sleep.
157  */
158 static int hdaps_readb_one(unsigned int port, u8 *val)
159 {
160 	int ret;
161 
162 	mutex_lock(&hdaps_mtx);
163 
164 	/* do a sync refresh -- we need to be sure that we read fresh data */
165 	ret = __device_refresh_sync();
166 	if (ret)
167 		goto out;
168 
169 	*val = inb(port);
170 	__device_complete();
171 
172 out:
173 	mutex_unlock(&hdaps_mtx);
174 	return ret;
175 }
176 
177 /* __hdaps_read_pair - internal lockless helper for hdaps_read_pair(). */
178 static int __hdaps_read_pair(unsigned int port1, unsigned int port2,
179 			     int *x, int *y)
180 {
181 	/* do a sync refresh -- we need to be sure that we read fresh data */
182 	if (__device_refresh_sync())
183 		return -EIO;
184 
185 	*y = inw(port2);
186 	*x = inw(port1);
187 	km_activity = inb(HDAPS_PORT_KMACT);
188 	__device_complete();
189 
190 	/* hdaps_invert is a bitvector to negate the axes */
191 	if (hdaps_invert & HDAPS_X_AXIS)
192 		*x = -*x;
193 	if (hdaps_invert & HDAPS_Y_AXIS)
194 		*y = -*y;
195 
196 	return 0;
197 }
198 
199 /*
200  * hdaps_read_pair - reads the values from a pair of ports, placing the values
201  * in the given pointers.  Returns zero on success.  Can sleep.
202  */
203 static int hdaps_read_pair(unsigned int port1, unsigned int port2,
204 			   int *val1, int *val2)
205 {
206 	int ret;
207 
208 	mutex_lock(&hdaps_mtx);
209 	ret = __hdaps_read_pair(port1, port2, val1, val2);
210 	mutex_unlock(&hdaps_mtx);
211 
212 	return ret;
213 }
214 
215 /*
216  * hdaps_device_init - initialize the accelerometer.  Returns zero on success
217  * and negative error code on failure.  Can sleep.
218  */
219 static int hdaps_device_init(void)
220 {
221 	int total, ret = -ENXIO;
222 
223 	mutex_lock(&hdaps_mtx);
224 
225 	outb(0x13, 0x1610);
226 	outb(0x01, 0x161f);
227 	if (__wait_latch(0x161f, 0x00))
228 		goto out;
229 
230 	/*
231 	 * Most ThinkPads return 0x01.
232 	 *
233 	 * Others--namely the R50p, T41p, and T42p--return 0x03.  These laptops
234 	 * have "inverted" axises.
235 	 *
236 	 * The 0x02 value occurs when the chip has been previously initialized.
237 	 */
238 	if (__check_latch(0x1611, 0x03) &&
239 		     __check_latch(0x1611, 0x02) &&
240 		     __check_latch(0x1611, 0x01))
241 		goto out;
242 
243 	printk(KERN_DEBUG "hdaps: initial latch check good (0x%02x)\n",
244 	       __get_latch(0x1611));
245 
246 	outb(0x17, 0x1610);
247 	outb(0x81, 0x1611);
248 	outb(0x01, 0x161f);
249 	if (__wait_latch(0x161f, 0x00))
250 		goto out;
251 	if (__wait_latch(0x1611, 0x00))
252 		goto out;
253 	if (__wait_latch(0x1612, 0x60))
254 		goto out;
255 	if (__wait_latch(0x1613, 0x00))
256 		goto out;
257 	outb(0x14, 0x1610);
258 	outb(0x01, 0x1611);
259 	outb(0x01, 0x161f);
260 	if (__wait_latch(0x161f, 0x00))
261 		goto out;
262 	outb(0x10, 0x1610);
263 	outb(0xc8, 0x1611);
264 	outb(0x00, 0x1612);
265 	outb(0x02, 0x1613);
266 	outb(0x01, 0x161f);
267 	if (__wait_latch(0x161f, 0x00))
268 		goto out;
269 	if (__device_refresh_sync())
270 		goto out;
271 	if (__wait_latch(0x1611, 0x00))
272 		goto out;
273 
274 	/* we have done our dance, now let's wait for the applause */
275 	for (total = INIT_TIMEOUT_MSECS; total > 0; total -= INIT_WAIT_MSECS) {
276 		int x, y;
277 
278 		/* a read of the device helps push it into action */
279 		__hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y);
280 		if (!__wait_latch(0x1611, 0x02)) {
281 			ret = 0;
282 			break;
283 		}
284 
285 		msleep(INIT_WAIT_MSECS);
286 	}
287 
288 out:
289 	mutex_unlock(&hdaps_mtx);
290 	return ret;
291 }
292 
293 
294 /* Device model stuff */
295 
296 static int hdaps_probe(struct platform_device *dev)
297 {
298 	int ret;
299 
300 	ret = hdaps_device_init();
301 	if (ret)
302 		return ret;
303 
304 	pr_info("device successfully initialized\n");
305 	return 0;
306 }
307 
308 static int hdaps_resume(struct platform_device *dev)
309 {
310 	return hdaps_device_init();
311 }
312 
313 static struct platform_driver hdaps_driver = {
314 	.probe = hdaps_probe,
315 	.resume = hdaps_resume,
316 	.driver	= {
317 		.name = "hdaps",
318 		.owner = THIS_MODULE,
319 	},
320 };
321 
322 /*
323  * hdaps_calibrate - Set our "resting" values.  Callers must hold hdaps_mtx.
324  */
325 static void hdaps_calibrate(void)
326 {
327 	__hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &rest_x, &rest_y);
328 }
329 
330 static void hdaps_mousedev_poll(struct input_polled_dev *dev)
331 {
332 	struct input_dev *input_dev = dev->input;
333 	int x, y;
334 
335 	mutex_lock(&hdaps_mtx);
336 
337 	if (__hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y))
338 		goto out;
339 
340 	input_report_abs(input_dev, ABS_X, x - rest_x);
341 	input_report_abs(input_dev, ABS_Y, y - rest_y);
342 	input_sync(input_dev);
343 
344 out:
345 	mutex_unlock(&hdaps_mtx);
346 }
347 
348 
349 /* Sysfs Files */
350 
351 static ssize_t hdaps_position_show(struct device *dev,
352 				   struct device_attribute *attr, char *buf)
353 {
354 	int ret, x, y;
355 
356 	ret = hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y);
357 	if (ret)
358 		return ret;
359 
360 	return sprintf(buf, "(%d,%d)\n", x, y);
361 }
362 
363 static ssize_t hdaps_variance_show(struct device *dev,
364 				   struct device_attribute *attr, char *buf)
365 {
366 	int ret, x, y;
367 
368 	ret = hdaps_read_pair(HDAPS_PORT_XVAR, HDAPS_PORT_YVAR, &x, &y);
369 	if (ret)
370 		return ret;
371 
372 	return sprintf(buf, "(%d,%d)\n", x, y);
373 }
374 
375 static ssize_t hdaps_temp1_show(struct device *dev,
376 				struct device_attribute *attr, char *buf)
377 {
378 	u8 temp;
379 	int ret;
380 
381 	ret = hdaps_readb_one(HDAPS_PORT_TEMP1, &temp);
382 	if (ret)
383 		return ret;
384 
385 	return sprintf(buf, "%u\n", temp);
386 }
387 
388 static ssize_t hdaps_temp2_show(struct device *dev,
389 				struct device_attribute *attr, char *buf)
390 {
391 	u8 temp;
392 	int ret;
393 
394 	ret = hdaps_readb_one(HDAPS_PORT_TEMP2, &temp);
395 	if (ret)
396 		return ret;
397 
398 	return sprintf(buf, "%u\n", temp);
399 }
400 
401 static ssize_t hdaps_keyboard_activity_show(struct device *dev,
402 					    struct device_attribute *attr,
403 					    char *buf)
404 {
405 	return sprintf(buf, "%u\n", KEYBD_ISSET(km_activity));
406 }
407 
408 static ssize_t hdaps_mouse_activity_show(struct device *dev,
409 					 struct device_attribute *attr,
410 					 char *buf)
411 {
412 	return sprintf(buf, "%u\n", MOUSE_ISSET(km_activity));
413 }
414 
415 static ssize_t hdaps_calibrate_show(struct device *dev,
416 				    struct device_attribute *attr, char *buf)
417 {
418 	return sprintf(buf, "(%d,%d)\n", rest_x, rest_y);
419 }
420 
421 static ssize_t hdaps_calibrate_store(struct device *dev,
422 				     struct device_attribute *attr,
423 				     const char *buf, size_t count)
424 {
425 	mutex_lock(&hdaps_mtx);
426 	hdaps_calibrate();
427 	mutex_unlock(&hdaps_mtx);
428 
429 	return count;
430 }
431 
432 static ssize_t hdaps_invert_show(struct device *dev,
433 				 struct device_attribute *attr, char *buf)
434 {
435 	return sprintf(buf, "%u\n", hdaps_invert);
436 }
437 
438 static ssize_t hdaps_invert_store(struct device *dev,
439 				  struct device_attribute *attr,
440 				  const char *buf, size_t count)
441 {
442 	int invert;
443 
444 	if (sscanf(buf, "%d", &invert) != 1 ||
445 	    invert < 0 || invert > HDAPS_BOTH_AXES)
446 		return -EINVAL;
447 
448 	hdaps_invert = invert;
449 	hdaps_calibrate();
450 
451 	return count;
452 }
453 
454 static DEVICE_ATTR(position, 0444, hdaps_position_show, NULL);
455 static DEVICE_ATTR(variance, 0444, hdaps_variance_show, NULL);
456 static DEVICE_ATTR(temp1, 0444, hdaps_temp1_show, NULL);
457 static DEVICE_ATTR(temp2, 0444, hdaps_temp2_show, NULL);
458 static DEVICE_ATTR(keyboard_activity, 0444, hdaps_keyboard_activity_show, NULL);
459 static DEVICE_ATTR(mouse_activity, 0444, hdaps_mouse_activity_show, NULL);
460 static DEVICE_ATTR(calibrate, 0644, hdaps_calibrate_show,hdaps_calibrate_store);
461 static DEVICE_ATTR(invert, 0644, hdaps_invert_show, hdaps_invert_store);
462 
463 static struct attribute *hdaps_attributes[] = {
464 	&dev_attr_position.attr,
465 	&dev_attr_variance.attr,
466 	&dev_attr_temp1.attr,
467 	&dev_attr_temp2.attr,
468 	&dev_attr_keyboard_activity.attr,
469 	&dev_attr_mouse_activity.attr,
470 	&dev_attr_calibrate.attr,
471 	&dev_attr_invert.attr,
472 	NULL,
473 };
474 
475 static struct attribute_group hdaps_attribute_group = {
476 	.attrs = hdaps_attributes,
477 };
478 
479 
480 /* Module stuff */
481 
482 /* hdaps_dmi_match - found a match.  return one, short-circuiting the hunt. */
483 static int __init hdaps_dmi_match(const struct dmi_system_id *id)
484 {
485 	pr_info("%s detected\n", id->ident);
486 	return 1;
487 }
488 
489 /* hdaps_dmi_match_invert - found an inverted match. */
490 static int __init hdaps_dmi_match_invert(const struct dmi_system_id *id)
491 {
492 	hdaps_invert = (unsigned long)id->driver_data;
493 	pr_info("inverting axis (%u) readings\n", hdaps_invert);
494 	return hdaps_dmi_match(id);
495 }
496 
497 #define HDAPS_DMI_MATCH_INVERT(vendor, model, axes) {	\
498 	.ident = vendor " " model,			\
499 	.callback = hdaps_dmi_match_invert,		\
500 	.driver_data = (void *)axes,			\
501 	.matches = {					\
502 		DMI_MATCH(DMI_BOARD_VENDOR, vendor),	\
503 		DMI_MATCH(DMI_PRODUCT_VERSION, model)	\
504 	}						\
505 }
506 
507 #define HDAPS_DMI_MATCH_NORMAL(vendor, model)		\
508 	HDAPS_DMI_MATCH_INVERT(vendor, model, 0)
509 
510 /* Note that HDAPS_DMI_MATCH_NORMAL("ThinkPad T42") would match
511    "ThinkPad T42p", so the order of the entries matters.
512    If your ThinkPad is not recognized, please update to latest
513    BIOS. This is especially the case for some R52 ThinkPads. */
514 static struct dmi_system_id __initdata hdaps_whitelist[] = {
515 	HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad R50p", HDAPS_BOTH_AXES),
516 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad R50"),
517 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad R51"),
518 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad R52"),
519 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad R61i", HDAPS_BOTH_AXES),
520 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad R61", HDAPS_BOTH_AXES),
521 	HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad T41p", HDAPS_BOTH_AXES),
522 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad T41"),
523 	HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad T42p", HDAPS_BOTH_AXES),
524 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad T42"),
525 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad T43"),
526 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T400", HDAPS_BOTH_AXES),
527 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T60", HDAPS_BOTH_AXES),
528 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T61p", HDAPS_BOTH_AXES),
529 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad T61", HDAPS_BOTH_AXES),
530 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad X40"),
531 	HDAPS_DMI_MATCH_INVERT("IBM", "ThinkPad X41", HDAPS_Y_AXIS),
532 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X60", HDAPS_BOTH_AXES),
533 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X61s", HDAPS_BOTH_AXES),
534 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad X61", HDAPS_BOTH_AXES),
535 	HDAPS_DMI_MATCH_NORMAL("IBM", "ThinkPad Z60m"),
536 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad Z61m", HDAPS_BOTH_AXES),
537 	HDAPS_DMI_MATCH_INVERT("LENOVO", "ThinkPad Z61p", HDAPS_BOTH_AXES),
538 	{ .ident = NULL }
539 };
540 
541 static int __init hdaps_init(void)
542 {
543 	struct input_dev *idev;
544 	int ret;
545 
546 	if (!dmi_check_system(hdaps_whitelist)) {
547 		pr_warn("supported laptop not found!\n");
548 		ret = -ENODEV;
549 		goto out;
550 	}
551 
552 	if (!request_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS, "hdaps")) {
553 		ret = -ENXIO;
554 		goto out;
555 	}
556 
557 	ret = platform_driver_register(&hdaps_driver);
558 	if (ret)
559 		goto out_region;
560 
561 	pdev = platform_device_register_simple("hdaps", -1, NULL, 0);
562 	if (IS_ERR(pdev)) {
563 		ret = PTR_ERR(pdev);
564 		goto out_driver;
565 	}
566 
567 	ret = sysfs_create_group(&pdev->dev.kobj, &hdaps_attribute_group);
568 	if (ret)
569 		goto out_device;
570 
571 	hdaps_idev = input_allocate_polled_device();
572 	if (!hdaps_idev) {
573 		ret = -ENOMEM;
574 		goto out_group;
575 	}
576 
577 	hdaps_idev->poll = hdaps_mousedev_poll;
578 	hdaps_idev->poll_interval = HDAPS_POLL_INTERVAL;
579 
580 	/* initial calibrate for the input device */
581 	hdaps_calibrate();
582 
583 	/* initialize the input class */
584 	idev = hdaps_idev->input;
585 	idev->name = "hdaps";
586 	idev->phys = "isa1600/input0";
587 	idev->id.bustype = BUS_ISA;
588 	idev->dev.parent = &pdev->dev;
589 	idev->evbit[0] = BIT_MASK(EV_ABS);
590 	input_set_abs_params(idev, ABS_X,
591 			-256, 256, HDAPS_INPUT_FUZZ, HDAPS_INPUT_FLAT);
592 	input_set_abs_params(idev, ABS_Y,
593 			-256, 256, HDAPS_INPUT_FUZZ, HDAPS_INPUT_FLAT);
594 
595 	ret = input_register_polled_device(hdaps_idev);
596 	if (ret)
597 		goto out_idev;
598 
599 	pr_info("driver successfully loaded\n");
600 	return 0;
601 
602 out_idev:
603 	input_free_polled_device(hdaps_idev);
604 out_group:
605 	sysfs_remove_group(&pdev->dev.kobj, &hdaps_attribute_group);
606 out_device:
607 	platform_device_unregister(pdev);
608 out_driver:
609 	platform_driver_unregister(&hdaps_driver);
610 out_region:
611 	release_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS);
612 out:
613 	pr_warn("driver init failed (ret=%d)!\n", ret);
614 	return ret;
615 }
616 
617 static void __exit hdaps_exit(void)
618 {
619 	input_unregister_polled_device(hdaps_idev);
620 	input_free_polled_device(hdaps_idev);
621 	sysfs_remove_group(&pdev->dev.kobj, &hdaps_attribute_group);
622 	platform_device_unregister(pdev);
623 	platform_driver_unregister(&hdaps_driver);
624 	release_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS);
625 
626 	pr_info("driver unloaded\n");
627 }
628 
629 module_init(hdaps_init);
630 module_exit(hdaps_exit);
631 
632 module_param_named(invert, hdaps_invert, int, 0);
633 MODULE_PARM_DESC(invert, "invert data along each axis. 1 invert x-axis, "
634 		 "2 invert y-axis, 3 invert both axes.");
635 
636 MODULE_AUTHOR("Robert Love");
637 MODULE_DESCRIPTION("IBM Hard Drive Active Protection System (HDAPS) driver");
638 MODULE_LICENSE("GPL v2");
639